Socket warpage reduction apparatus and method

ABSTRACT

Socket warpage reduction apparatus and method.

FIELD

[0001] The present invention is directed to socket warpage reduction.More particularly, the present invention is directed to socket warpagereduction apparatus and methods.

BACKGROUND

[0002] Electrical sockets may be used to secure electronic packagesand/or integrated circuit (IC) devices, for example, onto a system board(e.g. a mother board or a printed circuit board “PCB”) of an electronicsystem. These electrical sockets may be constructed for easyinstallation and replacement of electronic packages (e.g. electricalcomponents) and/or IC devices such as complex memory chips and advancedprocessor chips. The electrical sockets may also be available indifferent sizes and configurations, including, for example, LIF socketsand ZIF sockets.

[0003] LIF sockets may be suitable for detachably securing traditionalelectronic packages and/or IC devices with low pin counts onto a systemboard of an electronic system. However, ZIF sockets are more desirablefor advanced electronic packages and/or IC devices which have larger pincounts, since no or zero insertion force and removal force are required.For example, advanced processor chips with high pin counts are typicallyinstalled in a ZIF socket, which is soldered directly to a system boardof an electronic system. The ZIF sockets are commonly used to secureadvanced processor chips onto a PCB. This is because the advancedprocessor chips may be accommodated without fear of damaging the chipsor the electrical pins (connections) of the processor chips whichprovide electrical contacts from the processor chips to the systemboard.

[0004] A ZIF socket may typically include a release handle/lever which,when open, permits easy installation of an electronic package and/or anIC device such as a processor chip into the socket. Subsequent closureof the handle/lever may secure the processor chip in place.

[0005] However, these commonly available LIF and ZIF sockets, used forsecuring an electronic package and/or an IC device onto a system boardof an electronic system, contain several disadvantages, especially whenelectrical devices such as electronic packages or IC devices areinserted in LIF or ZIF sockets that have been secured onto a PCB of anelectronic system. One disadvantage that arises is related to theprocess of assembling a PCB. Some socket connectors are press-fit intothe PCBs or a LIF socket connector is employed. These press-fitconnectors are often used on double sided reflow circuit boards, whichare not processed through a wave solder machine. The presence ofdelicate and easily bent large pin number arrays on electrical and ICdevices require the devices to sit flush and squarely on the surface ofsocket connectors on the PCB. It follows that any planar warpage of asocket surface mount region will not mate uniformly with the planarelectronic devices, and such significantly increases the probabilitythat the pin array may not align perfectly with a pin aperture array inthe surface mount region of the socket. This results in a less thanperfect interconnection of the pins with the socket connector.

[0006] Socket connectors that have experienced a variety ofenvironmental conditions such as reflow and annealing may become twistedor turned, that is warped out of shape, which exacerbates pin insertionconcerns. Accordingly, there is a need to provide an apparatus andmethod to ensure that electrical sockets have a flat surface mountregion and, where warpage has arisen, there is a need to provide both anapparatus and method to flatten the surface mount region of the socket.

[0007] The problem of socket warpage is particularly vexing in ZIFsockets of the type that include a lever or a cam to secure anelectrical device to the socket, especially where the surface mountregion is present on a movable portion of a socket housing.

[0008] Warpage in ZIF sockets has been identified as a concern wheresocket designers have sought to ensure a flat surface mount region bythe inclusion of thin (e.g., sheet metal) reinforcing frames which areco-extensive with the perimeter of a top plate of the socket. The use ofthin reinforcing frames requires that the top plate to be reinforced isflat when the reinforcing frames are fitted to the edges i.e., perimeterof the top plate. This less advantageous approach at best, has limitedrigidity characteristics owing to the thin (sheet metal) frames, andthus does not provide for any structure to flatten a surface mountregion in the event that warpage of a surface mount region arises duringmolding, reflow or annealing processes routinely experienced in socketmanufacture and installation on a PCB.

[0009] Heretofore socket warpage has also been addressed by modifyingmold flow, mold compound or redesigning the socket so that warpage isreduced. As a socket gets larger in size, this becomes harder toaccomplish.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The foregoing and a better understanding of the present inventionwill become apparent from the following detailed description of exampleembodiments and the claims, when read in connection with theaccompanying drawings, all forming a part of the disclosure of thisinvention. While the foregoing and following written and illustrateddisclosure focuses on disclosing example embodiments of the invention,it should be clearly understood that the same is by way of illustrationand example only and that the invention is not limited thereto. Thespirit and scope of the present invention are limited only by the termsof the appended claims.

[0011] The following represents brief descriptions of the drawings,wherein:

[0012]FIG. 1 is a perspective view of a background cam activated ZIFsocket that is useful in gaining a more thoroughunderstanding/appreciation of the present invention;

[0013]FIG. 2 is a perspective view of another background ZIF socket thatis useful in gaining a more thorough understanding of the presentinvention;

[0014]FIG. 3 is an exploded view of the socket of FIG. 2;

[0015]FIG. 4 is a perspective view of yet another background example ofa ZIF socket useful in gaining a more thoroughunderstanding/appreciation of the present invention;

[0016]FIG. 5 illustrates a first portion of the example ZIF socket ofFIG. 4 with a lever rotated to a closed position;

[0017]FIG. 6 illustrates a corresponding mating portion of the ZIFsocket of FIG. 4 with a lever shown rotated in a closed position;

[0018]FIG. 7 is a perspective view of a background example of a ZIFsocket and an electronic package;

[0019]FIG. 8 is a top view of an example advanced cam actuated ZIFsocket embodiment of the invention;

[0020]FIG. 9 is a cross-section taken along line 9-9 in FIG. 8;

[0021]FIG. 10 is a cross-section taken along line 10-10 in FIG. 8;

[0022]FIG. 11 is a top view of another example advanced cam actuated ZIFsocket;

[0023]FIG. 12 is a top view of yet another example advanced leveractivated ZIF socket embodiment of the invention;

[0024]FIG. 13 is a section taken along line 13-13 in FIG. 12;

[0025]FIG. 14 is a side view of FIG. 12;

[0026]FIG. 15 is a top view of the arrangement of FIG. 12 wherein alever of FIG. 15 is shown in a closed position;

[0027]FIG. 16 is a top view of still yet another example advanced leveractuated ZIF socket embodiment of the invention;

[0028]FIG. 17 is a side view of FIG. 16; and

[0029]FIG. 18 is a top view of the arrangement of FIG. 16 wherein alever of FIG. 16 is shown in a closed position.

DETAILED DESCRIPTION

[0030] Before beginning a detailed description of the subject invention,mention of the following is in order. When appropriate, like referencenumerals and characters may be used to designate identical,corresponding or similar components in differing figure drawings. It isimportant to note that the present invention is not limited to theexamples and the example embodiment shown and described. In this regard,descriptive terms such as LIF socket and ZIF socket are intended tosuggest types of sockets wherein the present invention finds utility.Accordingly, the term socket is intended to describe a device designedto provide electrical connections and mechanical support for anelectronic or electrical component requiring convenient replacement. Itis to be further understood that the present invention is applicable foruse with all types of sockets, and all electronic packages and ICdevices, including new processor chips which may become available ascomputer technology develops in the future. Further, the presentinvention is not limited to use in computer systems, but is suitable forapplications in many industries and/or environments such as automotive,telecommunications, etc. However, for the sake of simplicity,discussions will concentrate mainly on exemplary use of a ZIF socket foruse on a system board of an electronic system, although the scope of thepresent invention is not limited thereto.

[0031] Attention is now directed to the drawings and particularly toFIG. 1, where there is shown a less advantageous ZIF socket 10 of a camactuated type which is used to secure an electronic device or electronicpackage such as a processor chip onto a system board of an electronicsystem. As shown in FIG. 1, the ZIF socket 10 may include sockethousings comprised of a top plate (cover) 10 a, a base, 20, and a cammechanism 30 (e.g., actuated through use of a hexagonal key (e.g., Allenwrench)). The top plate 10 a and the base 20 may be made from dielectricmaterials such as plastics, ceramics and other insulators, and can bevaried in sizes, shapes and openings to secure different types ofelectronic packages or IC devices onto a system board of an electronicsystem as desired. The top plate 10 a may be slidably mounted on thebase 20, as indicated by double headed arrow 21. The plate 20 may bemovable over a top surface of the base 20 between an open position and aclosed position in response to movement of the cam mechanism 30. The cammechanism 30 of the type illustrated will be explained ahead in fulldetail in conjunction with the description of FIGS. 7 to 9. The topplate 10 a of an example ZIF socket 10 may contain a plurality ofpin-insertion apertures 12 for accepting electrical pins from anelectronic package or electrical device, not shown in this figure, butshown and described in detail in other examples hereinafter. Theapertures 12 are shown deposed in a surface mount region 11.

[0032] The ZIF socket 10 is a typical socket that experiences warpage ofthe nature previously described and which the present inventionaddresses, all in a manner to be explained more fully hereinafter.

[0033] Attention is now directed to the perspective view of FIG. 2 andFIG. 3, in which there is depicted a ZIF socket 10 which includes a base20, a top plate or cover 10 a movably supported on the base 20 andadapted to retain an external electronic device, such as a processor(not shown). The base 20, best seen in FIG. 3, defines a plurality ofreceptacles 13 for receiving and retaining contact pins (not shown)therein. The top plate 10 a defines a plurality of pin insertionapertures 12 corresponding to the receptacles 13 for receiving pins ofthe external device whereby the pins extend through the apertures 12 andare partially received in the receptacles 13. Activation means (notshown), such as a caming mechanism or screwdriver, may be incorporatedin or used with the cam mechanism 30 for moving the top plate/cover 10 awith respect to the base 20 in a diagonal direction along a line betweenthe two ears 14, 15 of the base 20 thereby engaging the pins of theexternal device that extend through the apertures 12 of the top plate 10a and into the receptacles 13 of the base 20. The cover or top plate 10a is made of insulative material, such as plastic, and includes thin(sheet metal) reinforcing frames 17, 19, which are shown co-extensivewith the perimeter of the top plate 10 a. The frames 17, 19 are intendedto protect the top plate 10 a from an actuation force, but also to alimited extent, to enhance the rigidity thereof and suppress warpageduring manufacture and operation. The reason that the thin frames 17, 19only provided limited rigidity and warpage protection was because the ICdevice may have had a smaller pin array with fewer pins (than presentday devices), and the LIF/ZIF sockets may have had thicker bodies (i.e.,space/thickness/weight were low concerns), such that rigidity/warpagewere not high concerns.

[0034] Attention now is directed to FIGS. 4, 5, 6 and 7 wherespecifically FIG. 4 illustrates another less advantageous ZIF socket 10used to secure an electronic package onto an electronic system board.The ZIF socket 10 may include a top plate (cover) 10 a, a base 20, and acam mechanism 30. The top plate 10 a may be slidably mounted on the base20 as is indicated by double-headed arrow 21. The top plate 10 a may bemovable over a top surface of the base 20 between an open position and aclosed position in response to movement induced by the cam mechanism 30.

[0035] The top plate 10 a may contain a plurality of pin insertionapertures 12 for accepting electrical pins from an electronic packagesuch as an open die processor chip. The base 20 may contain acorresponding plurality of openings (receptacles) 22, housing springelements 24, each of which has a tail portion 26. The tail portions 26may protrude through a plurality of corresponding openings formed in thesystem board (not shown) and may be soldered, for example, to the systemboard circuitry of an electronic system. When the top plate 10 a is inan open position, that is, when the top plate 10 a moves in a firstdirection toward an open position, the electrical pins (e.g.connections) of an electronic package such as a processor chip may befreely inserted through the apertures 12 in the top plate 10 a and intotheir respective openings (receptacles) 22 in the base 20 and the springelements 24. When the top plate 10 a is in a closed position, that is,when the top plate moves in a second, opposite direction toward a closedposition, the electrical pins of an electronic package may be engagedphysically (e.g. pinched or welded) and electrically engage therespective spring elements 24 of the base 20. Conversely, when the topplate 10 a moves again back toward an open position, the pins of anelectronic package may be physically disengaged from the respectivespring elements 24 of the base 20 for ease of removal of the electronicpackage from the ZIF socket 10.

[0036] The cam mechanism 30 provides a means for sliding the top plate10 a over the base 20 between the open and closed positions. The cammechanism may be mounted in a tunnel shaped space between the top plate10 a and the base 20, and may be located inside a raised portion 37 ofthe top plate 10 a. The cam mechanism 30 may include a lever 32, whichis transversely connected to rotate a cam element to cause the top plate10 a to translate relative to the base 20. The lever 32 may contain anend portion 34, which is bent at an angle of approximately 15°-45° fromthe axis of the lever 32. The bent end 34 of the lever may allow for thelever 32 to be easily grasped for rotation in the horizontal directionto translate the top plate 10 a over the base 20 between open and closedpositions.

[0037] Refer now to FIG. 5, which depicts the base 20 disassembled fromthe top plate 10 a of the ZIF socket 10. In this illustration a channel28 has a generally T-shaped configuration that accommodates a camshaft29. The camshaft 29 is shown as a rod having a circular cross-sectionwith a jog 31 that functions as a cam lobe that provides an eccentricportion that can deliver an inward thrust for purposes of translatingthe top plate 10 a over the base 20, when lever 32 of the cam mechanism30 is rotated in a predetermined direction (e.g. horizontal direction).Alongside the channel 28 the base 20 includes an array of pin receivingreceptacles/openings 22 adapted to accommodate springs not shown and/orthe electrical pins from an electronic package such as a processor chip.

[0038] In FIG. 6 there is illustrated an underside view of the top plate10 a as it would be seen when the top plate 10 a is disassembled fromthe base 20. Note here that the jog/cam lobe 31 is positioned adjacentto a retaining post 16, 18 which thereby allows the transmission of acaming force to the retaining posts 16, 18 so as to generate a forcenecessary to translate the top plate 10 a over the base 20, when thelever 32 of the cam mechanism 30 is rotated in the predetermineddirection between open and closed positions.

[0039]FIG. 7 illustrates an example of a ZIF socket used for securing anelectronic package 33 onto a system board 500 of an electronic system.Such a system board 500 may be a commonly used board, known as a printedcircuit board (PCB) or a mother board which may contain a plurality ofthrough-holes 38 for solder mounting the ZIF socket for easyinstallation and replacement of electronic packages and/or IC devicesfrom the system board 500. The ZIF socket may include a top plate 10 a,a base 20 and a cam mechanism 30 assembled and ready for supporting theelectronic package 33. Here the electronic package 33 is shown having anopen die processor chip 35 disposed thereon. Optionally, position pins36 of the electronic package 33 and corresponding pin insertionapertures 12 of the ZIF socket 10 may be utilized to retain theelectronic package 33 relative to the ZIF socket 10.

[0040]FIG. 8 and FIG. 9, when studied in conjunction with thedescription that follows, will make apparent that FIG. 9 is a top viewof an example advanced ZIF socket 10′ that includes a socket housingcomprised of a top plate (cover) 10 a′ and a base 20′. The top plate 10a′ is movable in the direction indicated by the double-headed arrow 21′.The top plate 10 a′ further includes a surface mount region 11′ for anelectrical or electronic device not shown. Within the surface mountregion 11′ of the top plate 10 a′ there is provided an array of pininsertion apertures, such as the referenced aperture 12′.

[0041] In the manufacture and use of sockets or socket connectors, asthey are sometimes called, the sockets experience planar warpage thatinvolves the twisting or turning out of shape of the socket, whichresults in the socket's surface mount region no longer remaining flat asis necessary for the mounting thereon of large pin array electrical orelectronic devices.

[0042] The problem of warpage reduction in sockets is addressed in thepractice of the invention in the example of the advanced ZIF socket ofFIG. 8. In the practice of the present invention the sockets can be madeflatter when independent (rigid) bars or rods 40, 41 are inserted intogrooves 42, 43 (see FIG. 9) after the molding of the socket.(Hereinafter, within the description and claims, the term “bars” may beused generically to represent all viable types of rigid/warpage-reducingmembers, e.g., rods, boards, tubes, etc.) The insertion of the bars 40,41 into the grooves 42, 43 flattens the surface mount region 11′ whichguarantees the socket will meet flatness requirements, which willimprove yields, simplify contact insertion and ease of actuation byreducing warpage-induced friction that would arise between a warped topplate 10 a′ and a top surface of the base 20′. The grooves 42, 43 may beof a U-shaped cross-section and the bars 40, 41 may be rod shaped. Clips46, 47 may also be employed for clipping and retaining the bars into thegrooves.

[0043] It is important to appreciate that the warpage bars 40, 41 may beinserted into the top plate 10 a′ contiguous to the surface mount region11′ before or after any reflow processes, depending on needed assemblyflow. Alternative to insertion, the warpage bars may have the top plate10A′ injection-molded around such bars. Should the ZIF socket 10experience an annealing process, the process may benefit from the bars40, 41 being inserted or included before reflow, whereas warpagecorrection effects may be more beneficial after reflow.

[0044] The simple action of securing a socket to a printed circuit board(PCB) by means of solder balls (e.g., a scoket having a ball grid array(BGA) thereon), which are eutectic in nature, inherently involves areflow of the solder, that is the melting and resolidification of solderto form an electrical connection between the socket and PCB. It is notuncommon to discover after the reflow process that the socket has becomewarped and the surface mount region is no longer flat. Accordingly, anincrease in warpage usually occurs during reflow. It follows thereforethat the insertion of the rigid bars will be most advantageous. Socketsthat have experienced reflow often benefit from an annealing processthat relieves internal stress in the socket material.

[0045] By way of review it should be apparent that the highly advancedexample of the socket depicted in FIG. 8 and FIG. 9 is comprised ofsocket housing top plate 10 a′ having a surface mount region 11′ for anelectrical device and at least one rigid bar, such as bars 40, 41,secured in grooves 42, 43 and contiguous to the surface mount region11′, to thereby ensure the surface mount region 11′ is flat and remainsflattened in varying ambient conditions.

[0046] Attention is now directed to FIG. 8 and FIG. 10, which, whenstudied in conjunction with the description that follows, will explainthe nature of the cam mechanism 30′. In this example of the presentinvention the cam mechanism 30′ is not structurally significant to thewarpage reduction function of the warpage bars 40, 41. However, themovement of the top plate 10 a′ will now be explained in order tofacilitate a better comprehension of a ZIF socket environment in whichthe present example of the invention finds utility.

[0047]FIG. 10 illustrates a cross-section taken along line 10-10 in FIG.8 and reveals a cam 50 that includes a cam lobe 51 that engages the topplate 10 a′. The cam 50 further includes a cam stop 52 to make sure thecam 50 does not over rotate. The cam is provided with an opening 53 intowhich a tool (not shown) may be inserted to rotate the cam mechanism30′. A base cam post 54 is provided on which the cam 50 is mounted forrotation.

[0048] Turning now to FIG. 11 which is a top view of another exampleadvanced ZIF socket 10″ it will be observed that the top plate 10 a″ isprovided with a flat surface mount region 11″ for an electrical device.In this advantageous example a rigid U-shaped bar 60 is fitted into aU-shaped groove 61 in the same fashion that the rigid bars 40, 41 ofFIG. 8 were secured in grooves 42, 43 of FIG. 9. The U-shaped rigid bar60 is secured in the U-shaped groove 61 such that the surface mountregion 11″ for the electrical device is deposed within the U-shape ofthe U-shaped bar, to thereby ensure the surface mount region 11″ is flatand remains flattened in varying ambient conditions.

[0049] Turn now to FIGS. 12, 13, 14 and 15, which illustrate yet anotherexample of an advanced ZIF socket. FIG. 12 is a top view of a socket10′″ that provides a flat surface mount region 11′″ for an electricaldevice. The socket 10′″ is comprised of a top plate 10 a′″ adapted toprovide the flat surface mount region 11′″, which includes a pluralityof pin insertion apertures 12′″ adapted to permit insertion ofelectrical pin connections from the electrical device. The base 20′″,FIG. 10 includes a plurality of receptacles not shown in this figure ofthe nature shown and described earlier with respect to receptacles 13 inFIG. 3. The top plate 10 a′″ is slidably mounted on the base 20′″. A cammechanism 30′″ cooperates with the base 20′″ to slide the top plate 10a′″ over the base between an open and closed position in the mannershown and described in structural detail and function in FIGS. 4, 5, and6 hereinbefore.

[0050] A cam mechanism 30′″ is secured to the base 20′″ and cooperateswith the top plate 10 a′″ to slide the top plate 10 a′″ over the base20′″ between an open and closed position.

[0051] A lever 65 is coupled as shown to the cam mechanism 30′″ and ispivotally movable from an open position as shown in FIGS. 12 and 14 to aclosed position in FIGS. 13 and 15 to permit, in the open position, theinsertion of the electrical pin connections of the electrical devicethrough the top plate apertures 12′″ into the base receptacles (notshown). Pivotal movement of the lever 65 causes the top plate 10 a′″ tomove in relation to the base 20′″ to a closed position thereby causingthe electrical pin connectors to be secured in the receptacles in thebase.

[0052] The surface mount region 11′″ in the top plate 10 a′″ includes afirst groove 66 having a U-shaped cross-section. The first groove 66 islocated contiguous to the surface mount region 11′″. Movement of thelever 65 from the open to closed positions causes the lever to securelyengage the groove 66 (see FIG. 15) in the top plate 10 a′″ to therebyensure that the top plate and surface mount region is flat and remainsflattened in varying ambient environments. Again, clips 46, 47 may beused for clipping and retaining the lever 65 into the groove 66. In theevent that there is a need for an even grater assurance that surfacemount region 11′″ is flat, the present invention may also employ a rigidbar 40′ secured in a second groove 67 (FIG. 13) parallel to the firstgroove 66, such that an electrical device positioned on the surfacemount region 11′″ is deposed between the rigid bar 40′ in the secondgroove 67 and the lever 65 when the lever 65 is in the closed positionand occupying the first groove 66.

[0053] By way of summary it will be readily appreciated in this advancedexample of the present invention that the lever 65 works as both anactuation mechanism and a warpage reduction bar. The rigid lever 65 andthe rigid bar 40′ together can make sockets flatter when other answersare not workable. Independent bars or rods make it possible to mold thehousing and then flatten it. Where a warpage feature such as theaforementioned (BACKGROUND) thin (sheet metal) frame is secured to a topplate perimeter, the molding process may also warp the warpage framefeatures. The present invention using rigid bars or rods advantageouslyensures a straightening effect to a socket surface mount region thatguarantees the socket will meet flatness requirements, thereby improvingyields, simplifying contact insertion and actuation by reducing warpageinduced friction.

[0054] It is to be further noted that in the event an annealing processis involved in the manufacture and use of the present FIGS. 12-15invention, then the annealing process may benefit from warpage barsbeing inserted before reflow, whereas warpage correction effects may bemore beneficial after reflow.

[0055] Turn now to yet another example of an advanced ZIF socketillustrated in FIGS. 16, 17 and 18. Here again, as in FIG. 12, there isa top view of a zero-insertion force socket 10″″ that provides a flatsurface mount region 11″″ on a top plate 10 a″″. A cam mechanism 30″″ issecured to a base 20″″, as shown in FIG. 17 and cooperates with the topplate 10 a″″ to slide the top plate over the base between an open andclosed position. A U-shaped lever 69, best seen in FIG. 18 in a closedposition and in an open position in FIGS. 16, 17, is coupled to the cammechanism 30″″ at ends 68, 71 of the U-shaped lever 69 and is pivotallymovable from an open position, (FIG. 16) to a closed position (FIG. 18).The top plate 10 a″″ is provided with a U-shaped groove 70, as bestobserved in FIG. 16. The U-shaped groove 70 is located on the top plate10 a″″ such that legs of the U-shaped groove 70 thereby cause, uponmovement of the lever from the open to the closed position, the U-shapedlever to securely engage the U-shaped groove 70 in the top plate 10″″.The pressure of the U-shaped lever 69 in the U-shaped groove 70 ensuresthat the top plate 10 a″″ and the surface mount region is flat andremains flattened.

[0056] In the broadest sense, the present invention involves a methodcomprising the forming of at least one groove in a socket housingcontiguous to a surface mount region for an electrical device andinserting one of a rigid bar and rod in the groove to thereby ensurethat the surface mount region is flat and remains flat in varyingambient conditions. The method just set forth also contemplates asfollowing within the spirit of the present invention, forming a secondgroove in the top plate and inserting a one of a second bar and rod inthe top plate parallel to the one groove and bar such that the surfacemount region is deposed between rigid bars or rods in parallel grooves.

[0057] The inventive method of the present invention also involvesforming a U-shaped groove in a socket housing contiguous to a surfacemount region for an electrical device, and inserting a U-shaped rigidbar or rod in a mating relationship in the U-shaped groove to provide asurface mount region for an electrical device within the U-shape of theU-shaped groove to thereby ensure that the surface mount region is flatand remains flattened in varying ambient conditions.

[0058] Another advanced method of the present invention involvesestablishing a flat surface mount region in a zero-insertion forcesocket that includes:

[0059] a socket housing having a top plate adapted to provide the flatsurface mount region, the top plate providing a plurality of pininsertion apertures adapted to provide for insertion of electrical pinconnections from the electrical device;

[0060] a base that has a plurality of receptacles adapted to receive pinelectrical connections provided by the electrical device, the pinconnections extending through the apertures in the top plate and intothe receptacles;

[0061] the socket housing top plate and base have the capacity to sliderelative to each other;

[0062] a cam mechanism that is secured to the base and cooperates withthe top plate to slide the top plate over the base from an open to aclosed position; and

[0063] a lever coupled to the cam mechanism, wherein the lever ispivotally movable from an open position to a closed position to providein the open position the insertion of the electrical pin connectors ofthe electrical device through the top plate apertures and into the basereceptacles, whereupon pivotal movement of the lever to the closedposition causes the electrical pin connectors to be secured in thereceptacles in the base.

[0064] The other advanced method further involves forming a groove inthe socket top plate of the socket housing contiguous to the surfacemount region, and then moving the lever from its open position to theclosed position to thereby cause the lever to securely engage the groovein the top plate and thereby ensure that the top plate and surface mountregion are flat and remain flattened in varying ambient conditions.

[0065] The present invention involves yet another method of establishinga flat surface mount region a zero-insertion force socket that includes:

[0066] a socket housing having a top plate adapted to provide the flatsurface mount region, the top plate providing a plurality of pininsertion apertures adapted to provide for the insertion of electricalpin connections from the electrical device;

[0067] a base that has a plurality of receptacles adapted to receive pinelectrical connections provided by the electrical device, the pinconnections extending through the apertures in the top plate and intothe receptacles;

[0068] the socket housing top plate and base with the capacity to sliderelative to each other;

[0069] a cam mechanism that is secured to the base and cooperates withthe top plate to slide the top plate over the base from an open to aclosed position; and

[0070] a U-shaped lever coupled to the cam mechanism at the ends of theU-shaped lever, wherein the U-shaped lever is pivotally movable from anopen position to a closed position to provide in the open position theinsertion of the electrical pin connections of the electrical devicethrough the top plate apertures and into the base receptacles, whereuponpivotal movement of the lever to the closed position causes theelectrical pin connectors to be secured in the receptacles in the base.

[0071] This method further involves forming a U-shaped groove in thesocket top plate of the socket housing such that the surface mountregion for the electrical device is disposed within the legs of theU-shaped groove, and then moving the U-shaped lever from its openposition to a closed position, thereby causing the U-shaped lever tosecurely engage the U-shaped groove in the top plate when the U-shapedlever is moved from the open to the closed position, thereby ensuringthat the top plate and surface mount region is flat and remainsflattened in varying ambient conditions.

[0072] In concluding, reference in the specification to an exampleembodiment, etc., means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the invention. The appearances of suchphrases in various places in the specification are not necessarily allreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anyembodiment, it is submitted that it is within the purview of one skilledin the art to effect such feature, structure, or characteristic inconnection with other ones of the embodiments. Furthermore, for ease ofunderstanding, certain method procedures may have been delineated asseparate procedures; however, these separately delineated proceduresshould not be construed as necessarily order dependent in theirperformance, i.e., some procedures may be able to be performed in analternative ordering, simultaneously, etc.

[0073] This concludes the description of the example embodiments.Although the present invention has been described with reference to anumber of illustrative embodiments thereof, it should be understood thatnumerous other modifications and embodiments can be devised by thoseskilled in the art that will fall within the spirit and scope of theprinciples of this invention. More particularly, reasonable variationsand modifications are possible in the component parts and/orarrangements of the subject combination arrangement within the scope ofthe foregoing disclosure, the drawings and the appended claims withoutdeparting from the spirit of the invention. In addition to variationsand modifications in the component parts and/or arrangements,alternative uses will also be apparent to those skilled in the art.

[0074] For example, the electrical contacts of the pin insertionapertures may be available in a variety of size and shapes withdifferent projections. The cam mechanism may include different drivingelements such as worn gears, wedges, ratchets, etc. Moreover, thecamshaft of the cam mechanism may be positioned at various angles andmay work with different sized and/or shaped levers. The overalldimensions of the ZIF socket may be altered depending upon theelectrical elements used, the desired strength, the structural rigidity,and the thermal stability.

[0075] Of equal importance it is to be understood that the base uponwhich a top plate of the socket may slide will also benefit from the useof bars/rods inserted into grooves on the surface of the base to ensurethat the top plate and base slide freely with respect to each other.Many modifications may be made to adapt the teachings of the presentinvention to a particular situation without departing from the scopethereof. Therefore, it is intended that the present invention not belimited to the various exemplary embodiments disclosed, but that thepresent invention includes all embodiments falling within the scope ofthe appended claims.

What is claimed is:
 1. A socket comprising: a socket housing having asurface mount region for an electrical device, and at least one rigidbar secured in a groove in the socket housing and contiguous the surfacemount region to thereby ensure the surface mount region is flat andremains flattened in varying ambient conditions.
 2. The socket asclaimed in claim 1, wherein the groove is a U-shaped channel.
 3. Thesocket as claimed in claim 2, wherein the rigid bar is a rod.
 4. Thesocket as claimed in claim 1, wherein there is provided a second rigidbar secured in another groove in the housing substantially parallel tothe rigid bar and disposed adjacent the surface mount region such thatan electrical device positioned on the surface mount region is disposedbetween the one rigid bar and the second rigid bar.
 5. The socket asclaimed in claim 2 wherein the grooves are U-shaped channels.
 6. Thesocket as claimed in claim 2, wherein each rigid bar is a rod.
 7. Anelectrical socket to provide a flat surface mount region for anelectrical device, the socket comprising: a U-shaped rigid bar securedin a mating U-shaped groove such that the surface mount region for theelectrical device is disposed within the U-shape of the U-shaped bar tothereby insure the surface mount region is flat and remains flattened invarying ambient conditions.
 8. The socket as claimed in claim 7, whereinthe U-shaped groove is a channel having a U-shaped cross-section.
 9. Thesocket as claimed in claim 8, wherein the U-shaped rigid bar has a rodshaped cross-section.
 10. A zero insertion force socket that provides aflat surface mount region for an electrical device, the socketcomprising: a top plate adapted to provide a flat surface mount region,the top plate having a plurality of pin insertion apertures adapted topermit insertion of electrical pin connections from the electricaldevice, a base having a plurality of receptacles adapted to receive thepin electrical connections of the electrical device that extend throughthe apertures in the top plate and into the receptacles, the top plateis slidably mounted on the base, a cam mechanism is secured to the baseand cooperates with the top plate to slide the top plate over the basebetween an open and closed position, a lever is coupled to the cammechanism and is pivotally movable from an open position to a closedposition to permit in the open position the insertion of the electricalpin connections of the electrical device through the top plate aperturesand into the base receptacles, whereupon pivotal movement of the levercauses the top plate to move in relation to the base to a closedposition, thereby causing the electrical pin connectors to be secured inthe receptacles in the base, and the flat surface mount region includesa first groove in the top plate that is contiguous to the surface mountregion, whereupon movement of the lever from the open to closed positioncauses the lever to securely engage the groove in the top plate tothereby ensure that the top plate and the surface mount region is flatand remains flattened in varying ambient environments.
 11. The socket asclaimed in claim 10, wherein the flattened surface mount region in thetop plate includes adjacent the surface mount region a rigid bar securedin a second groove parallel to the first groove such that an electricaldevice positioned on the surface mount region is disposed between therigid bar in the second groove and the lever when the lever is in theclosed position and occupying the first groove.
 12. The socket asclaimed in claim 11, wherein the grooves are U-shaped channels.
 13. Thesocket as claimed in claim 12, wherein the rigid bar and lever are rodshaped.
 14. A zero insertion force socket that may be actuated andprovides a flat surface mount region for an electrical device, thesocket comprising: a top plate adapted to provide a flat surface mountregion, the top plate having a plurality of pin insertion aperturesadapted to permit insertion of electrical pin connections from theelectrical device, a base having a plurality of receptacles adapted toreceive the pin electrical connections of the electrical device thatextend through the apertures in the top plate and into the receptacles,the top plate is slidably mounted on the base, a cam mechanism issecured to the base and cooperates with the top plate to slide the topplate over the base between an open and closed position, a U-shapedlever is coupled to the cam mechanism at ends of legs of the U-shapedlever and is pivotally movable from an open position to a closedposition to permit in the open position the insertion of the electricalpin connections of the electrical device through the plate apertures andinto the base receptacles whereupon pivotal movement of the lever to theclosed position causes the electrical pin connectors to be secured inthe receptacles in the base, and the top plate is provided with aU-shaped groove such that the surface mount region for the electricaldevice is disposed within legs of the U-shaped groove to thereby cause,upon movement of the lever from the open to the closed position, theU-shaped lever to securely engage the U-shaped groove in the top plateand thereby ensure that the top plate and the surface mount region isflat and remains flattened in varying ambient conditions.
 15. The socketas claimed in claim 14, wherein the U-shaped grooves have a U-shapedcross-section.
 16. The socket as claimed in claim 15, wherein U-shapedlever has a rod shaped cross section.
 17. A method comprising: formingat least one groove in a socket housing contiguous to a surface mountregion for an electrical device, and inserting a rigid bar in the grooveto thereby ensure that the surface mount region is flat and remains flatin varying ambient conditions.
 18. The method as claimed in claim 17,wherein the forming of the groove comprises: providing the groove with aU-shaped cross-section.
 19. The method as claimed in claim 18, whereinthe rigid bar comprises: a rod. 20 A method comprising: forming a pairof grooves in a socket housing contiguous to a surface mount region foran electrical devise, and inserting rigid bars in the grooves to therebyensure the surface mount region is flat and remains flattened in varyingambient conditions.
 21. The method as claimed in claim 20, wherein theforming of the grooves comprises: providing the grooves with a U-shapedcross-section.
 22. The method as claimed in claim 21, wherein the rigidbars comprise: rods. 23 A method comprising: forming a U-shaped groovein a socket housing contiguous to a surface mount region for anelectrical device, and inserting a U-shaped rigid bar in a matingrelationship in the U-shaped groove to provide a surface mount regionfor an electrical device within the U-shape of the U-shaped bar in theU-shaped groove to thereby ensure that the surface mount region is flatand remains flattened in varying ambient conditions.
 24. The method asclaimed in claim 23, wherein the forming of the U-shaped groovecomprises: providing the U-shaped groove with a U-shaped cross-section.25. The method as claimed in claim 24, wherein the rigid bar comprises:a rod.
 26. A method comprising: establishing a flat surface mount regionin a zero insertion force socket for an electrical device, wherein thezero insertion force socket comprises: providing a socket housing havinga top plate adapted to provide the flat surface mount region, the topplate providing a plurality of pin insertion apertures adapted toprovide for insertion of electrical pin connections from the electricaldevice, providing a base that has a plurality of receptacles adapted toreceive pin electrical connections provided by the electrical device,the pin connections extending through the apertures in the top plate andinto the receptacles, providing the socket housing top plate and basewith the capacity to slide relative to each other, providing a cammechanism that is secured to the base and cooperates with the top plateto slide the top plate over the base from an open to a closed position,providing a lever coupled to the cam mechanism, wherein the lever ispivotally movable from an open position to a closed position to providein the open position the insertion of the electrical pin connectors ofthe electrical device through the top plate apertures and into the basereceptacles, whereupon pivotal movement of the lever to the closedposition causing the electrical pin connectors to be secured in thereceptacles in the base, and forming a groove in the socket top plate ofthe socket housing contiguous to the surface mount region, and movingthe lever from its open position to closed position to thereby cause thelever to securely engage the groove in the top plate and to therebyensure that the top plate and surface mount region are flat and remainflattened in varying ambient environments.
 27. The method as claimed inclaim 26, wherein the lever and groove comprise: a rod and a groovehaving a U-shaped cross-section.
 28. A method comprising: establishing aflat surface mount region in a zero insertion force socket for anelectrical device, wherein the zero insertion force socket comprises:providing a socket housing having a top plate adapted to provide theflat surface mount region, the top plate providing a plurality of pininsertion apertures adapted to provide for the insertion of electricalpin connections from the electrical device, providing a base that has aplurality of receptacles adapted to receive pin electrical connectionsprovided by the electrical devise, the pin connections extending throughthe apertures in the top plate and into the receptacles, providing thesocket housing top plate and base with the capacity to slide relative toeach other, providing a cam mechanism that is secured to the base andcooperates with the top plate to slide the top plate over the base froman open to a closed position, providing a U-shaped lever coupled to thecam mechanism at the ends of the U-shaped lever, wherein the U-shapedlever is pivotally movable from an open position to a closed position toprovide in the open position the insertion of the electrical pinconnections of the electrical device through the top plate apertures andinto the base receptacles, whereupon pivotal movement of the lever tothe closed position causes the electrical pin connectors to be securedin the receptacles in the base, forming a U-shaped groove in the sockettop plate of the socket housing such that the surface mount region forthe electrical device is disposed within the legs of the U-shapedgroove, and moving the U-shaped lever from its open position to a closedposition, thereby causing the U-shaped lever to securely engage theU-shaped groove in the top plate when the U-shaped lever is moved fromthe open to the closed position, thereby ensuring that the top plate andsurface mount region is flat and remains flattened in varying ambientconditions.
 29. The method as claimed in claim 28, wherein the U-shapedlever comprises: a rod formed in a U-shape.
 30. The method as claimed inclaim 29, wherein the U-shaped groove comprises: a groove having aU-shaped cross-section.